The specific goals of this protocol are 1) to define the acute effect of oral nutrient intake on PTH and calcium levels and salt regulation, 2)to test the hypothesis that the hypertensive changes from salt loading may be mediated by PTH, and 3) to determine whether some hypertensive subjects have and abnormality in regulation of salt and calcium. We will compare the results in hypertensives with those of normal controls. Uses CDMAS facility only.